Observing Mars 
By Tim Printy

A few years ago, I made the remark that through the years, I had trained myself
to see better.  Actually, that statement is not quite accurate as it was pointed
out to me.  I had not improved my eyesight in anyway.  What I really meant was
that I had trained myself to notice subtle details on the planets and deep sky
objects.  You learn to look for small details.  Years of experience has shown me
this.  None of my photographs every noticed as much detail as I was able to see
with the unaided eye.   CCD's are the only things that approach what an observer
can see with the eye.  How do you get this trained eye?  The only way is to look
at the planets and start trying to see more than what the cursory look gives you.
 When observing Mars in 1988, I found out that after about 10-15 minutes,
features that I did not notice initially, suddenly began to jump out.  This was
just  a matter of looking at the major details and then trying to look for more
detail.  You too can develop this ability.  All you need to do is sit down and
watch.

Mars has many prominent features that can be viewed at time of opposition.  The
first thing that can be observed is the polar ice cap(s).  Often the planet is
tilted towards earth and only one cap is visible.  The southern cap is prominent
in the summer and fall months, while the north cap is tilted towards us in
winter/spring (like this opposition).  I separate the planet into several regions
of 90 degrees longitude each.  These are dominated by some prominent features. 
The first is from 0-90 degrees (I designate Region I).  This is a very
interesting region.  The northern latitudes of this area is dominated by Mare
Acidalium while the southern area contains Aurorae Sinus and Mare Erythraeum. 
While these names are hard to pronounce, you quickly learn to identify them. 
Also visible in this region are some smaller features including my favorite,
Solis Lacus (Commonly called the "eye of Mars").  Just north of this feature is
the feature Tithonius which marks the area of the super valley, Vallis Marinaris.
 This region will be visible around early to mid March (assuming that you observe
around 10PM EST).  Region 2 comprises of very few features from 90-180 degrees
longitude.  Here, the Tharsis volcanoes dominate.  They often appear as bright
features (esp Olympus Mons) on the red surface.  To the south is mare Sirenum but
the rest of the region is mostly featureless and will appear all red to the
casual observer.  Pay attention to these areas however, as you may catch glimpses
of clouds around the volcanoes and smaller features.  This area will be most
visible in early March or mid April.  Region III is from 180-270 degrees
longitude.  Mare Cimmerium is in the south as well as Mare Tyrrehenum.  The two
are separated by a "channel" of red Martian dust.  To the north is the feature
Utopia.  Also visible are several volcanic regions near Elysium.  This is visible
around the end of March.   The last region, Region IV, reveals some of Mars most
prominent features.  The big triangular Syrtis Major is located at the planets
equator and will dominate the view.  South of this feature is a large circular
bright area called Hellas.  To the north is the feature BoreoSyrtis.  In
addition, there is a long dark extension which goes east-west and ends in a
fist-like feature.  This feature is called Sinus Sabaeus.  This area will be most
prominent towards the end of March.

Observing Mars is quite the chore.  Mars rotates once every  24.6 hours.  This
means if you are watching from night to night, the same features will be visible
for comparison from the previous night.  After about a week, the facing of mars
will shift to give you new features to look at.   What can you look for?  For
openers, you can monitor the polar caps for changes.    In addition to the polar
caps, you can observe clouds and fogs forming on the planet.  These are most
prominent in the Tharsis regions.  Use a Violet or Blue filter to see the upper
clouds.  If the cloud appears brighter/larger in a green filter, this is probably
a fog.  Orographic clouds  form the infamous "W" clouds visible near Tharsis and
also form clouds near the Elysium volcanoes.  This is most common during aphelic
oppositions (like this one) and they can be quite bright. They can also be seen
in the Hellas/Argyre basins in late spring/early summer.

Dust storms are major events and appear initially as yellow clouds which can be
detected with a yellow filter.  Orange and red filters will give contrast to the
cloud and may reveal the shadows of these clouds.  Yellow clouds are most common
during the peak of Martian summer (mid to late fall for us earthlings).  They
often originate in the Solis Lacus, Hellas, Chryse, Isidis, Thoth , and Casius
regions.  Check out the maps provided by Astronomy or Sky and Telescope  to
determine the locations of these regions.  The dust storms provide a
redistribution of dust around the planet and will often change the features
significantly.  This is why studying the planet at every opposition is important
so as to monitor and identify these changes.  This month, and next, you can get a
chance to observe Mars.  Even though it is not extremely favorable, it still will
give you a chance to enjoy the red planet and to train yourself for future, more
favorable oppositions.